MELBOURNE, Australia, Monday July 4, 2016 – New research has shown that stress can turn the body’s lymphatic system into a “super highway” for breast cancer cells, accelerating the spread of the disease.
Experts have long debated to what extent stress affects a patient’s prognosis, and while stress has not been proved to cause cancer, a team of Australian scientists now says it may play a significant role in how it spreads.
Cancer biologist Dr Erica Sloan and her team at Monash University studied how stress drives metastasis — the spread of cancer from an original tumour — in mice with breast cancer. According to Dr Sloan: “Stress sends a signal into the cancer that allows tumour cells to escape from the cancer and spread through the body.” “The stress is sort of acting like a fertiliser and helping the tumour cell take hold and colonise those other organs.”
She added that although it was already known that cancer could spread through the lymphatic system, her team discovered that stress transformed the network into a super highway that allowed the cancer cells to travel at far faster speeds.
For the research, the scientists put mice with cancer in confined spaces to mimic the physiological and emotional effects of stressed humans. Dr Caroline Lee, who was part of the research team, said the effect the stress had on their cancer was marked.
“You see six times more spread of cancer in stressed mice compared to control mice,” she said. Dr Sloan’s team nevertheless found that a drug currently used for high blood pressure and cardiac arrhythmia could prevent the stress from boosting the spread of the disease.
The medication contains beta blockers which prevent the stress response by competing with adrenalin to limit heart rate and blood pressure increase. When the beta blockers were given to the mice with cancer, the stress response was completely negated. The stress no longer restructured the lymphatic system that led to the increased cancer spread.
Over at the Peter MacCallum Cancer Centre in Melbourne, anaesthetist Dr Jonathan Hiller is currently conducting a pilot trial in humans. Dr Hiller’s trial is focusing on anxiety in female surgical patients recently diagnosed with breast cancer.
“We’ve chosen the peri-operative period because, as an anaesthetist, we often see women have a state of increased stress and anxiety at the time of surgery, and the build-up to surgery following diagnosis can be incredibly anxiety provoking,” Dr Hiller explained.
In his double-blind trials, patients are given either the beta blocker Propanolol or a placebo, and their stress levels before and after surgery are recorded via blood samples. Stress signatures which are present in white blood cells are being analysed to see if the beta blocker can change the stress signatures at the time of surgery.
Depending on the results of Dr Hiller’s ongoing research, a cancer-specific beta blocker that is designed to target tumours, not the heart, could be developed.